INTERCOMPARISON OF A.C. MAGNETIC MEASUREMENTS ON ELECTRICAL SHEET STEELS USING A SINGLE SHEET TESTER (COLLECTION OF INDIVIDUAL REPORTS)

Abstract

The document is the collection of the individual reports of the laboratories which participated in the intercomparison campaign. The object of this intercomparison was to determine the level of agreement between major national and industrial metrology laboratories specialising in the measurement of the magnetic properties of various qualities of steel used in the construction of electrical machines and transformer cores. Measurements of specific total power loss, specific apparent power and relative magnetic permeability were made at a frequency of 50 Hz on 20 sheets, each 500 x 500 mm, using a single sheet tester in accordance with IEC Standard 404, Part 3, 1982. For commercial grading purposes, there was found to be good agreement between 5 out of the 6 participants for specific total power loss measurements and agreement between all participants for permeability measurements. For specific apparent power measurements it is recommended that the reproducibility is increased to 5% as the magnetic circuit conditions vary from user to user. In addition, the intercomparison has shown that a single value of effective magnetic path length of 450 mm could be adopted for the IEC single sheet tester. This value gives the best compromise when comparing results from the sheet tester with measurements in the hitherto used Epstein frame.

Additional information

Authors: CEC
CEC BRUXELLES (BE), CEC BRUXELLES (BE)

Bibliographic Reference: EUR 12368 EN (1990) 288 PP., MF, ECU 12 AVAILABLE FROM THE OFFICE FOR OFFICIAL PUBLICATIONS OF THE EUROPEAN COMMUNITIES, L-2985 LUXEMBOURG